How Man United's threadbare defence has been in torn apart

Chris Smalling was stupidly sent off against City while Marcos Rojo injured his shoulder and had to be stretchered off.

It left United's back four that finished the derby as one of the worst in their history: Luke Shaw, Michael Carrick, Paddy McNair and Antonio Valence.

Starsport charts the catalogue of problems that have beset United at the back this year.

March 5: Inter Milan confirm they have agreed a deal to sign Serbian defender Nemanja Vidic from United. He leaves at the end of the 2013-14 season.

May 12: United confirm Rio Ferdinand, a key component of the Red Devils' back line for 12 years, will leave in the summer.

June 27: Left-back Luke Shaw is signed for £27m plus add-ons.

July 21: Patrice Evra also exits the club, joining Juventus, even though he signed a one-year contract extension at United in May.

July 29: United boss Louis van Gaal announces he has had to devise a special training programme for Shaw, whom he describes as "not very fit".

August 13: United confirm Shaw will miss first four weeks of the season with a hamstring injury.

August 20: Argentina defender Rojo, who played at full-back for his country at the 2014 World Cup, moves to Old Trafford from Sporting Lisbon.

August 24: Smalling suffers a groin injury in the 1-1 draw at Sunderland.

September 1: Daley Blind, who can play in defence or in midfield, is signed on deadline day from Ajax. The window closes with United having spent around £150m on new players but no recognised central defender.

September 12: Versatile defender Phil Jones is ruled out for up to a month with a hamstring injury.

September 21: Defender Jonny Evans suffers a foot injury in a calamitous 5-3 defeat at Leicester, with Smalling replacing him as he made his own return from the groin problem sustained in August. Another defender, Tyler Blackett, is sent off and therefore suspended.

September 24: Smalling suffers a new injury - this time to his thigh - in training.

September 25: Van Gaal confirms he is down to just one fit centre-back - Rojo - for the game against West Ham.

September 27: Nineteen-year-old Paddy McNair is drafted in for a senior debut against the Hammers. He also features against Everton and Manchester City.

October 26: Van Gaal reveals Jones is suffering from shin splints which caused him to miss the 1-1 draw with Chelsea, in which Smalling made his return from injury. Jones also missed the Manchester derby.

November 2: Smalling sent off for two bookable offences against Manchester City, while Rojo suffers a suspected dislocated shoulder. Brazilian full-back Rafael misses the match due to injury so winger Antonio Valencia is forced to fill in. United end the match with McNair and midfielder Carrick occupying the central defensive positions.